Method of arc welding

ABSTRACT

A method of arc welding is disclosed in which a consumable electrode of predetermined composition and the same composition in granular or powdered form are fed separately to the weld area, so that variations in the amount of consumable electrode and granular or powdered composition are of no consequence, and the composition of the deposit will always remain constant. The necessity for careful control of the ratio of feed is thus eliminated, and, moreover, the pool of molten material under the arc is substantially cooler than that of the pool in other or conventional submerged arc welding methods, with the result that there is less dilution of the pool by the base or substrate.

Umted States Patent [151 3,674,979 Cape July 4, 1972 [54] METHOD OF ARCWELDING Primary ExaminerJ. V. Truhe Assistant Examiner-Gale R. Peterson[72] Inventor. Arthur T. Cape, Monterey, Calif. Atmmey lSler and Omstein[73] Assignee: Coast Metals, Inc., Little Ferry, NJ. 22 Filed: Sept. 23,1970 [57] ABSTRACT [52] US. Cl... ...2l9/l37,2l9/146,2l9/76 [51] Int. Cl..B23k 9/00 [58] Field ofSearch ..2l9/76, 137, 145

[56] References Cited UNITED STATES PATENTS 3,296,408 III 967 Arnoldy..2l9/76 3,513,283 5/1970 Arnoldy ..2l9/76 3,177,340 4/1965 Danhier..2l9/46 A method of arc welding is disclosed in which a consumableelectrode of predetermined composition and the same composition ingranular or powdered form are fed separately to the weld area, so thatvariations in the amount of consumable electrode and granular orpowdered composition are of no consequence, and the composition of thedeposit will always remain constant. The necessity for careful controlof the ratio of feed is thus eliminated, and, moreover, the pool ofmolten material under the arc is substantially cooler than that of thepool in other or conventional submerged arc welding methods, with theresult that there is less dilution of the pool by the base or substrate.

4 Claims, No Drawings METHOD OF ARC WELDING Bulkwelding is a submergedarc welding process or method in which an arc is passed between aconsumable metal electrode, usually mild steel wire, and a granularmetal alloy composition deposited in measured or metered amounts on thebase material or work, to produce a deposit on the base material or workof an alloy consisting of the melted wire and the melted granular alloycomposition. The method involves maintaining or attempting to maintain aconstant deposition relationship or ratio between the consumableelectrode and the granular alloy composition.

Such a method, involving the use of a solid wire as the consumable metalelectrode, the use of a rotatable feed wheel for metering the amount ofgranular or powder metal alloy composition to the weld area, and meansfor automatically coordinating the depositing of the alloy powder andthe electrode wire to form the alloy weld or deposit having a closelycontrolled analysis, is described in U.S. Pats. Nos. 3,060,307;3,172,991 and 3,260,834.

A variation of the method described in the aforesaid patents isdescribed in US. Pat. No. 3,513,288, in which, instead of a wire, astrip of mild steel is formed into a consumable tubular electrode ofrelatively large diameter, and the granular alloy material is fed, inmetered amounts, into the tube at a point just above that at which thestrip is closed to form the tube, the granular material flowing throughthe tube.

In such a process, since all of the alloying ingredients, with theexception of the steel wire or tube, are deposited independently of thewire or tube, and even though it is attempted to maintain a constantdeposition relationship or ratio between the wire or tube and thegranular alloy composition, any variations in the ratio of the amount ofwire or tube to the amount of granular alloy composition or powderchanges the composition of the deposit.

ln Pat. No. 3,060,307, reference is also made to a ductile tube method,used primarily for hardfacing, in which a tube of ductile metal, whichis the matrix metal, and containing carbide-forming and other hardnessproducing elements, is used. In usihg this ductile tube method todeposit an alloy such as Stellite 6, a tube made of ductile cobaltstrip, and containing the other alloying material in powder form, inamounts which, when melted with the tube, forms the Stellite 6, is used,but it has been found that the pool under the arc is extremely hot,causing the base metal to dilute the coating, producing a coating ordeposit which is very high in iron, that is to say, 25 percent or over,unless stringent precautions are taken to prevent or avoid this.

If, however, the filled cobalt tube is used as the consumable electrode,and, at the same time, a Stellite 6 composition, in granular or powderform, is fed separately into the melt, any variations in the ratio ofthe amount of filled tube to the amount of granular alloy or powder,thus separately supplied to the melt, are of no consequence, since bothare of the same composition, and the composition of the deposit willalways remain constant.

The necessity for careful control of the ratio of feed is thuseliminated, and, moreover, the pool of molten material under the arc issubstantially cooler than that of the pool to which reference haspreviously been made, with the result that there is less dilution of thepool by the base or substrate, so that the deposit will contain lessthan 10 percent iron, which is compatible with the results produced byconventional oxyacetylene welding. l have found that oxy-acetylene weldsof Stellite 6 material will contain small amounts of iron, but wherelarge partsare being welded for hardfacing, the iron in the depositsinvariably range well above 6 percent.

An example of the proposed process or method is one in which the tubularportion of the consumable filled electrode consists of cobalt, and thegranular filler material or powder within the tube is a composition suchthat when the filled electrode is melted, the deposit will be of thefollowing composition, known as Coast Metal No. 6:

Carbon Chromium Nickel 3.0 Max. Molybdenum 1.0 Max. Tungsten 3.5 to 5.5%Iron 3.0 Max. Silicon 0.90 to 1.50% Manganese 0.50 Max. Cobalt BalanceThe granular alloy composition which is fed to the pool of molten metalseparately is also of the same composition as stated above, and may befed to the pool in any desired manner, that is to say, in a manner notnecessarily requiring the use of a metering wheel.

The tubular portion of the electrode may be made from cobalt strip, inthe manner described in my US. Pat. No.

, 3,483,724, and may be filled with the granular material of powder inthe course of manufacture of the electrode, or the tubular electrode maybe a seamless tube of cobalt, which is filled with the granular materialor powder.

The method or process which is proposed by this patent applicationconsists broadly therefore in providing a tubular consumable electrodeof cobalt or nickel, within which is enclosed material, in granular orpowder fonn, which, when melted with the tubular electrode, provides adeposit of an alloy consisting of the tube and filler, and, at the sametime, separately feeding to the pool of molten alloy thus formed agranular material, which, when melted, forms an alloy of the samecomposition as said deposit.

The method or process also encompasses the use, in such a process, of analloy which can be made in the fonn of a solid wire, that is, anunfilled wire, to provide a melted deposit of such alloy, and, at thesame time, separately feeding to the pool of alloy thus formed, agranular material, which, when melted, forms an alloy of the samecomposition formed by the melted solid wire.

Although the invention has been described with reference to an alloy ofthe type in which cobalt is the predominant or matrix-formingconstituent, it is to be understood that the invention is alsoapplicable to any of the Stellite type alloys, as well as alloys of theHastelloy t particularly Hastelloy C, in

.which nickel is the predominant or matrix-forming constituent. In thelatter case, the tubular portion of the consumable electrode would bemade of nickel strip. An example of such a nickel-base alloy, known asCoast Metal No. has the following composition:

Carbon 0.08 Max. Molybdenum 16 to 17% Silicon 1.0 Max. Cobalt 2.5 Max.Tungsten 3.75 to 4.5% Manganese 1.0 Max. Chromium 15 to 16.5% Iron 4 to7% Vanadium 0.2 to 0.35% Nickel Remainder Carbon 1.50 to 1.90% Chromium34.0 to 36.0% Copper 1.75 to 2.25% Silicon 2.00 Max. lron Balance Wherethe consumable electrode can be in wire form, and it is not necessary toprovide a filled tube to form the alloy, the invention or process wouldthen consist in feeding the alloy wire to the weld area, and, at thesame time,

separately feeding the same alloy, in granular or powder form,

to the weld area.

Having thus described my invention, 1 claim:

made of an alloy,

1. The method of producing a deposit on an area of a substrate,comprising the steps of feeding an alloy, in granular or powder form,onto said area, creating an electric arc with a consumable electrode ofthe same composition as said alloy, when melted, between said granularalloy and said electrode to melt said electrode and said granular alloy,said consumable electrode consisting of a tube of a metal elementselected from the group consisting of cobalt, nickel and iron, and afiller of granular material, which, when melted with said tube, providesa deposit of the same composition as said granular alloy when melted,and feeding both the electrode and granular alloy continuously and at ameasured rate during the melting of the electrode to provide an alloydeposit on said area consisting of said molten alloy electrode andmolten granular alloy.

2. The method, as defined in claim 1, wherein said consumable electrodeconsists of a tube of cobalt, and a granular filler, which, when meltedwith said tube, produces a deposit of the following composition:

Carbon 0.9 to 1.40% Chromium 26.0 to 30.0% Nickel 3.0 Max. Molybdenum1.0 Max. Tungsten 3.5 to 5.5% Iron 3.0 Max. Silicon 0.90 to 1.50%Manganese 050 Max. Cobalt Balance 3. The method, as defined in claim 1,wherein said consumable electrode consists of a tube of nickel, and agranular filler, which, when melted with said tube, produces a depositof the following composition:

Carbon 0.08 Max. Molybdenum 16 to 17% Silicon 1.0 Max. Cobalt 2.5 Max.Tungsten 3.75 to 4.5% Manganese 1.0 Max. Chromium 15 to 16.5% Iron 4 to7% Vanadium 0.2 to 0.35% Nickel Remainder 4. The method, as defined inclaim 1, wherein said consumable electrode consists of a tube of iron,and a granular filler, which, when melted with said tube, produces adeposit of the following composition:

Carbon 1.50 to l.90% Chromium 34.0 to 36.0% Copper 1.75 to 2.25% Silicon2.00 Max. lron Balance

2. The method, as defined in claim 1, wherein said consumable electrode consists of a tube of cobalt, and a granular filler, which, when melted with said tube, produces a deposit of the following composition: Carbon 0.9 to 1.40% Chromium 26.0 to 30.0% Nickel 3.0 Max. Molybdenum 1.0 Max. Tungsten 3.5 to 5.5% Iron 3.0 Max. Silicon 0.90 to 1.50% Manganese 0.50 Max. Cobalt Balance
 3. The method, as defined in claim 1, wherein said consumable electrode consists of a tube of nickel, and a granular filler, which, when melted with said tube, produces a deposit of the following composition: Carbon 0.08 Max. Molybdenum 16 to 17% Silicon 1.0 Max. Cobalt 2.5 Max. Tungsten 3.75 to 4.5% Manganese 1.0 Max. Chromium 15 to 16.5% Iron 4 to 7% Vanadium 0.2 to 0.35% Nickel Remainder
 4. The method, as defined in claim 1, wherein said consumable electrode consists of a tube of iron, and a granular filler, which, when melted with said tube, produces a deposit of the following composition: Carbon 1.50 to 1.90% Chromium 34.0 to 36.0% Copper 1.75 to 2.25% Silicon 2.00 Max. Iron Balance 